Department of Pharmaco-Biochemistry, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Shizuoka, Japan.
J Cell Physiol. 2010 Mar;222(3):481-7. doi: 10.1002/jcp.21988.
Transient receptor potential melastatin 6 (TRPM6) channel is involved in the reabsorption of magnesium in the kidney. We recently found that TRPM6 expression is up-regulated by EGF, but the regulatory mechanism has not been clear. TRPM6 mRNA was endogenously expressed in HEK293 cells. TRPM6 mRNA expression was increased by EGF, which was inhibited by U0126, an MEK inhibitor. Promoter activity of human TRPM6 was observed in the TRPM6 5'-flanking region from -1,214 to -718. This promoter activity was enhanced by EGF and inhibited by U0126. Three putative AP-1 binding sites were identified within the region of -1,214/-718. The mutation of the putative AP-1 binding site (-741/-736) completely inhibited the EGF-induced promoter activity. EGF increased p-ERK1/2, c-Fos, c-Jun, and p-c-Jun levels, which were inhibited by U0126. The introduction of c-Fos or c-Jun siRNA inhibited the EGF-induced promoter activity. A chromatin immunoprecipitation assay revealed that c-Fos and c-Jun bind to the AP-1 binding site within the region of -1,214/-718. These results suggest that EGF up-regulates TRPM6 mRNA expression mediate via the activation of ERK/AP-1-dependent pathway.
瞬时受体电位 melastatin 6（TRPM6）通道参与肾脏镁的重吸收。我们最近发现表皮生长因子（EGF）可上调 TRPM6 的表达，但调控机制尚不清楚。TRPM6mRNA 在 HEK293 细胞中内源性表达。EGF 可增加 TRPM6mRNA 的表达，而 MEK 抑制剂 U0126 则可抑制其表达。在人类 TRPM6 的 5'-侧翼区 -1,214 到-718 处观察到 TRPM6 启动子活性。EGF 可增强该启动子活性，而 U0126 则可抑制其活性。在 -1,214/-718 区鉴定出三个潜在的 AP-1 结合位点。潜在的 AP-1 结合位点（-741/-736）突变完全抑制了 EGF 诱导的启动子活性。EGF 增加了 p-ERK1/2、c-Fos、c-Jun 和 p-c-Jun 的水平，而 U0126 可抑制这些水平。c-Fos 或 c-Jun siRNA 的导入抑制了 EGF 诱导的启动子活性。染色质免疫沉淀试验表明 c-Fos 和 c-Jun 可与 -1,214/-718 区的 AP-1 结合位点结合。这些结果表明，EGF 通过激活 ERK/AP-1 依赖性途径上调 TRPM6mRNA 的表达。
